DCC power

I am new to dcc operation and my question is how much power do I need for a layout that is approx. 12'x 24' and right now I can run 4 trains. My problem is that when I have them all running they go very slow. Do I need more amps in my transformer? or do I need more volts? I am currently using an old transformer for
AC hookup. I am using command 2000. Any help would be appreciated. Thank You

I am not familiar with the requirements of the Command 2000, but almost always you need a new, more stout power supply. For the Digitrax system, the requirements state a transformer of 16 to 20-volts AC or DC. I believe you are "drawing down" the transformer as you add more locos. With my 18-volt power supply, I consistently run 8 to 10 locos at once with no power loss. My advice is to get ahold of MRC and ask the experts what the system requirements are.
Robert

The MRC system only puts out a maximum of 2.5 Amps. Don't hook a larger supply or you'll cook the unit. Were you running regular DC on the layout then just converted to DCC? The reason I ask is to find out how the layout was running pre-DCC if it was at all. You should be providing your system with 14V and approx 2.5 amps to function. What kind of locomotives are you running? Do you how many amps each one draws on the system? Does the speed differ with only one or to locomotives running vs. 3 or 4? If this is the case, you are underpowering your layout. But a quick call to MRC would be a good idea after you check how much current your locomotives are using.

Having used the MRC DCC equipment myself on a layout about a quarter of your size I found the following issues. First, the larger the gauge of wire you use matters (I use 14 Gague for the bus & 18 Ga for the drops). Several drops are needed, as depending on the rail joiners to pass the current is asking too much of them. I agree with the other comments, that the number of locos and their amp usage is most likely what wrong here. Finally, I was using the recremonded 22 Ga phone line for the hand held unit. I solved most of my troubles by replacing it with 14 Ga instead (costs more, but worth the effort). For a layout the size of yours you might have to add additional boosters, but I don't know of any that are compatable with the MRC system (Model Railroader ran an article earlier this year about a generic booster, I think it was from CVP Products {they make Easy DCC}). I'd also contact MRC directly. I've made the move to Digitrax myself, as the limitations of the handheld unit for MRC would work for me, as I wanted to be able to control any of my locos from the handheld without reprogramming their addresses.